In the industry of pharmaceutical and medical use products, it is necessary to have containers ensuring suitable asepsis and hygiene conditions for the products that they contain until the time they are used, usually by healthcare personnel and in some cases by the actual patient.
This type of container comprises a body of impermeable material, which is obtained from a reel of multilayer film (for example, of polyester and/or polyurethane), in which housings suitable for the product to be contained are continuously configured, (for example by means of thermoforming, thermoforming with suction, molding, etc) and a closing sheet which is sealed on the edges of the body of impermeable material, the mentioned closing sheet comprising a material that is permeable to ethylene oxide. The closing sheet is obtained from a continuously fed reel of film which is arranged on the housings formed from a reel of multilayer film and after it is sealed, the unitary containers are cut or separated.
The sterilization of this type of container is carried out once the container is hermetically sealed by means of the closing sheet, containing the object or product to be sterilized. Said sterilization is carried out by inserting the container in an asepsis chamber, which is hermetically closed, a bath of the container being carried out by means of the diffusion of ethylene oxide (normally mixed with other gases) in gaseous state. By means of said bath, ethylene oxide penetrates into the container through the sheet that is permeable thereto and sterilizes its interior, as well as the product contained in the container, eliminating possible microbes and spores.
The atmosphere of the chamber is then stabilized so that the application of ethylene oxide acts suitably for a certain time, and the gas is then extracted or evacuated from the chamber, for example by means of gas absorbers or exhausters, a completely impermeable container the interior of which is suitably sterilized thus being obtained.
The previously described sterilization process is common to many types of aseptic containers for containing medical or pharmaceutical products or objects.
In the containers described in the previous paragraph, as has been indicated, the material that is permeable to ethylene oxide is in the closing sheet of the container, there being currently two types of containers, according to the arrangement of said permeable material and the process for obtaining the closing sheet.
On one hand, there are containers in which the closing sheet is obtained directly from a reel of material that is permeable to ethylene oxide, such that the entire surface of the closing sheet is made of material that is permeable to ethylene oxide, which involves an unnecessary cost increase of the container due to the fact that the cost of said material is much higher than that of the multilayer material in which the body of the container is manufactured.
On the other hand, there are containers in which both the body and the closing sheet are manufactured from a reel of multilayer film (for example of polyester and polypropylene), an inner portion of the closing sheet being cut once the closing sheet has been sealed on the corresponding body of the container, the material that is permeable to ethylene oxide being arranged in the space freed up by said cut, by means of heat sealing.
The aseptic container AMCOR®, corresponding to the multinational company DUPONT®, can be mentioned as a commercial example of this type of container, which container comprises the use of TYBET® sheets of material that is permeable to ethylene oxide, which are used to handle a large variety of sterile products in the medical and pharmaceutical sector, achieving a suitable protection of the contained product, such as for example gowns or any type of disposable medical garment, thus increasing the life and the hygienic conditions of the content of the container during its packaged period.
The problem of this type of container is that it requires the use of an expensive and complex machine and it furthermore increases the waste of multilayer film.